Cherokee, Synqor bus converters target 12 V

Tustin, Calif. - Two new bus converters from Cherokee International here and Synqor (Hudson, Mass.) set their sights on the 12-volt intermediate bus as a suitable takeoff point for powering multiple point-of-load converters in distributed-power architectures.

Cherokee International's C-BUS converter (CBQ2548G1) is a quarter-brick that provides 25 amps at a nominal 12 volts. Synqor's half-brick can deliver up to 240 watts at 5 or 12 V and is also useful in applications requiring more stringent output regulation.

The offerings from both companies thus pursue a somewhat different design path for so-called two-stage power conversion architectures that take a nominal 48-V input to power the bus converter, which in turn powers point-of-load (nonisolated) converters delivering low voltage (e.g., 1 to 3.3 V) to loads downstream.

The Cherokee unit provides a loosely regulated 12-V isolated intermediate bus from a relatively tight 42- to 53-V input and delivers an efficiency of 96 percent. It's touted as a smart dc transformer running open loop to maximize efficiency and output current and yet minimize component count. The converters are available in both positive- and negative-logic versions.

Protection features for the Cherokee unit include circuitry for overcurrent, overvoltage and overtemperature, and input undervoltage. They include automatic restart after shutdown due to a fault. There is no minimum-load requirement. They meet basic insulation requirements per EN60950. The C-BUS comes in both open-frame and base plate versions. They're priced at $49 each in 1,000-piece quantities. Samples are available through the company.

Synqor's PowerQor Peta line, on the other hand, delivers what the company describes as a tightly regulated 12 V at 20 A or 5 V at 45 A, and thus can be used as a single-output dc/dc module or as a wide-input (36- to 75-V) bus converter. It delivers an efficiency greater than 93 percent.